The following are some supplements of particular interest for cancer survivors:
Vitamin D seems to have anti proliferative effects that may be especially beneficial for decreasing cancer progression and enhancing survival, at least based on animal studies. Low circulating 25-hydroxy vitamin D [25(OH) D], the recommended biomarker of vitamin D status, is linked to an increased risk of several cancers. Observational studies tie higher 25(OH)D levels to improved outcomes among colorectal cancer survivors and possibly breast cancer survivors. But even when low circulating 25(OH) D is associated with worse outcomes in observational studies, it isn’t clear whether supplementation changes prognosis.
It’s unclear whether the Institute of Medicine’s 25(OH) D, recommendation of 600 to 800 IU daily based on bone health are adequate, for bone or overall health among cancer survivors. Some researchers propose targeting serum 25(OH)D levels of at least 30 ng/mL or 40 to 80 ng/mL in the survivor population, with an intake of 1,000 to 2,000 IU of vitamin D commonly recommended to reach those levels but still not established as optimal.
A concern among breast and prostate cancer survivors is the risk of osteoporosis secondary to surgical, chemotherapy, or hormonal therapies that decrease estrogen or testosterone levels, respectively, or following long-term corticosteroid use. While aiming for bone- and cancer-protective benefits, researchers emphasize that evidence is lacking regarding the safety of high blood levels of vitamin D.
Glutamine is an essential amino acid of interest for its potential to aid mouth sores and other symptoms of mucositis and to improve peripheral neuropathy that develops as a side effect of chemotherapy. It supports gastrointestinal cell growth and regeneration, and it may reduce the production of inflammatory cytokines. Significant side effects are uncommon with oral glutamine supplementation. More research on its use is needed, but caution is advised among patients with hepatic or renal insufficiency because, since it’s an amino acid, the liver and kidneys must metabolize glutamine. In patients with liver or renal insufficiency on protein restriction, glutamine supplementation should be avoided so as not to burden these organs.
Glutamine is used in clinical practice as a powder mixed into oral solution, generally “swished” before swallowing for mucositis benefit.
This is a hormone secreted by the pineal gland, holds dual interest for cancer survivors. For those who have difficulty falling asleep, doses of 0.5 to 3 mg at bedtime may be helpful. Emerging evidence suggests that melatonin may provide cancer-protective effects by upregulating antioxidant enzymes and suppressing factors that promote cancer development. Limited data show some improvement in mortality rates when used at higher doses as an accompaniment to conventional cancer therapy.
Since melatonin can alter estrogen levels and may interact with drugs metabolized through certain pathways, those considering use should consult their physicians.